Composition board



july 22 '1924. 1,502,603

C. O. WALFER n COMPOSITION BOARD original FiledAug- 2o. m21' Patentes .Bury 22, i924.

CURRY ORA WALPER,

or DETROIT, MICHIGAN, AssrGNoR, BY DIRECT AND Masini ASSIGNMENTS, TO STANDARDPLASTERING SYSTEM, OF DETROIT, MICHIGAN, A

LORPOItl-ITION 0F MICHIGAN.

CMPOSITION BOARD.

l @riginal application led August 20,

in place of the usual woodv or. metal lath and rough plaster for interior walls and ceilings, or in place of the various bases upon which stucco is applied to 'form eX- terior walls.

Another object of the invention is to utilize a product hitherto considered as iwaste, as a` building material for interior or exterior use, in constructing walls resistant to heat, at a cost considerably less than that of the materials nowordinarily employed.

A further object of the invention is -to provide a wall board havinga surface adapted for the proper adhesion of a finishing coat of plaster.

A still further object is the provision of a finishing coat adhesion to the board described herein and suited for easy application thereto as a smooth and fire resisting finish.

In the drawing, lthe figure represents a transverse section of a fragment of a wall board embodying my invention. f

In the preferred construction of wall board, a' plastic composition is used consisting of the waste produce vof asbestos manufacture mixed with asuitable quantity of gypsum plaster. Asbestos occurs in veins of fibrous magnesium silicate. The surrounding rock is usually of a similar composition but is not so fibrous. After most of the fibrous'asbestos has been removed, the rock mined 'therewith containing some fibrous asbestos is usually discarded and considered as waste. It is sold in limited quantities as rough asbestic or rough asbestic is crushed, the resultant asbestic somewhat.` resembles a mixture of finely 'divided asbestos and talc. Mixed with a suitable plaster, such as the ordinary to i elements ofy for a wall board adapted for `is too porous the tailings When this l 1921, Serial No. 493,921. Divided and this application led July 24, 1922. Serial No. 576,970.

Jblue plaster containing calcined gypsum and lime, from five to fifty per cent of the plastic composition may consist, ofl asbestic to forma suitable body for use as a fireproofw'all board. f

A composition of plaster and asbestos permits nails to be driven therethrough without cracking and by the use of nail sets, the heads may be countersunk and covered by the finishing coat for additional protection, yet the composition is so poor a conductor of heat that a three-eighths inch board of this material will prevent ignition of paper on the surface opposite a ame for a longer 'period than an inch thickness of ordinary,

plaster would.

Another waste product of asbestos manufacture is what is known as asbestos sandings, this material being the portion removed from the surface and edges of asbestos boards by grinding or sandpapering. This waste material consists of asbestos fibers and cement and is similar in its qualities to the crushed asbestio.

Itis of course obvious that asbestos itself may be used with plaster to form a board of even better` quality than that produced by the usevof asbestic or asbestos sandings.

This board having such a large percentage of asbestos is lighter than plaster for the same thickness, but since it is iireproof a board may be used thinner than the ordinary plaster.

Another important advantage of the board ossessing so high a percentage of asbestic 1s the acoustic quality. Walls in which such boards are used will be less resonant than walls finished with aA surface coating of hard plaster especially plaster containing a considerable percentage of ealcined gypsum.

In order that a finishing coat may adhere properly to the rough coat of a plastered wall` or to a wall board there must be a certain suction. In other words the rough coat or wall board must be sufficiently porous to absorb some of the moisture from the nishing coat. If a rough coat or plaster board water willY be withdrawn from theJ finishing coat so rapidly that not enough will remain for proper hydration of the gypsum contained in the finishing coat. If the rough coat or plaster board is not suiliciently porous, the finishing mcoat willv set as a separate layer with very little adhesion tothe rough coat or plaster board. In either case the linishing coat will be likely to crack and fall olf.

To secure the proper adhesion, the degree of suction of the present Wall board is regulated by the use of a size of casein or other suitable material applied to the surface of the wall board.

The mixture of crushed asbestic contains sufficient grit to obviate the necessity for the use of any sandwhen mixed with calcined gypsum and a suitable quantity of water to form a smooth flowing plastic composition. The boards may be molded of the desired thickness eitherin. panels of a` fixed length and width or as a continuous strip capable ofbeing cut up at the factory into various commercial sizes. Before the plastic composition has become set a sanding coat of coarse calcined gypsum is sprinkled over the surface absorbing a suicient quantity of water from the wet composition toadhere and to form a very satisfactory surface for the adhesion ofthe finishing coat. After the sanding coat has been applied the size of casein maybe applied either while the board is still wet or after it has become dry and hard. In some cases it may be preferred to apply the sizing of casein after the wall board is in position in a building structure.

The finishing coat will preferably consist of a` reproof composition consistingv of -crushed rough asbestos, calcined gypsum and lime. The function of the lime is to make the plastic composition easier of application as a. smooth finishing coat, and in order to prevent too rapid setting of the 40 gypsum, al suitablerf'quantity of commercial retarder may be used. While the present composition is resistant to compression when it has set, it is still capable of penetration by nails and their heads can be countersunkthird layer comprising" a plastic composialmost as in wood.

It will be seen that the present material provides a plaster board much'more highly resistant to heat than any other composition boards now in general use. The fact that the crushed asbesticis at present a-waste product enables the production of this board to be accomplished at a lower cost than many other wall boards.`

This application is a division of my application filed August 20, 1921, Serial, No.

493,921, Patent1,448,886, Mar. 20, 1923.-

The structure shown in the drawing illustrates a preferred form of wall board in which wire reinforcing fabrics are used advent separation of-the plastic center from the metallic back. The reinforcing strips are preferably secured to the backing 1.

It will be obvious that many modifications in the proportions of the various ingredients may be made within certain limits without sacrificing the advantages of the composition. I do not therefore wish to be limited to the exact percentages described, but desire to claim the invention in any of its scope of the following claims.

I claim v 1. A wall board comprising a plastic composition containing crushed rough asbestic.

2. A, wall board comprising a plastic composition containing crushed rough asbestic and gypsum plaster. s

3. A wall 'board comprising a plastic composition containing from live to fifty per cent crushed rough asbestic, and calcined gypsum. Y

4. A wall board comprising a plastic composition containingcrushed rough asbestic and calcined gypsum, and having a Asurface layer of coarse calcined gypsum.

5. A Wall comprising a layer of a plastic composition consisting of crushed rough asbestic and calcined gypsum and a layer consisting of a plastic composition of crushed coarse calcined asbestic, gypsumand lime.

6.I A wall comprising a layer consisting of a plastic composition of crushed rough asbestic and calcined gypsum having an adhering second layer thereon of coarse calcined gypsum coated with casein and having a third layer adhering to the second, said cURRY oRA WALPER. Witnesses AnTHUR MINNICK, CHARLES- W. Sramana.

'modications within the legitimate and valid y 

